EiffelTestCaseStartedEvent sample missing TEST_CASE_EXECUTION link

[lmcstbi]

See: https://github.com/Ericsson/eiffel/blob/master/examples/events/EiffelTestCaseStartedEvent/simple.json

According to https://github.com/Ericsson/eiffel/blob/master/eiffel-syntax-and-usage/the-links-object.md the TEST_CASE_EXECTUION link is required for this event.

[d-stahl-ericsson]

Good catch, thanks! Would you be willing to post a PR fixing the example?